Oil in coolant

2001 VOLKSWAGEN PASSAT
118,000 MILES • 4 CYL • AUTOMATIC
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BOBBYWYATT86
  • MEMBER
  • 1 POST
2001 Passat. Check engine light came on. Autozone's free check found an O2 sensor went bad. Upon having that fixed, my mechanic-friend noticed oil residue in my coolant tank. I have since heard a few theories about the root of it: the head gasket, a seal broken on a washer, and the oil cooler. My actual mechanic believes the oil cooler to be the problem. Who is right? And should I get a new reservoir and hoses put in, like someone else I know, or would that not really help at all?
Feb 1, 2011 at 4:38 PM
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JACOBANDNICKOLAS
  • Experienced Mechanic
  • 110,240 POSTS
First, you need to determine if it is engine oil or transmission fluid. If it is motor oil, have a compression test done to see if there are any low cylinders. Also, check the transmission fluid to make sure no coolant is getting into the transmission.
Apr 4, 2011 at 4:39 AM
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